Dieting reduces plasma tryptophan and alters brain 5-HT function in women.
A three week low calorie diet significantly reduced both total plasma tryptophan and the ratio of tryptophan to competing amino acids in a group of 15 healthy volunteers. Despite a similar percentage weight loss the reduction in plasma tryptophan was greater in women than men. In addition, only in women was dieting associated with increased prolactin secretion following intravenous tryptophan, a measure of brain 5-hydroxytryptamine (5-HT) function. These results suggest that dieting reduces the availability of circulating tryptophan for brain 5-HT synthesis. Women appear more vulnerable than men both to this effect and to its consequences for brain 5-HT function. Altered brain 5-HT function may play a part in some of the psychological consequences of dieting, including the development of clinical eating disorders.
Anderson
I M
IM
University of Oxford, Department of Biochemistry.
Parry-Billings
M
M
Newsholme
E A
EA
Fairburn
C G
CG
Cowen
P J
PJ
D000328:Adult; D000597:Amino Acids, Branched-Chain / Q000097:blood; D015992:Body Mass Index; D001921:Brain / Q000502:physiology*; D004038:Diet, Reducing / Q000523:psychology*; D002149:Energy Intake / Q000502:physiology*; D005260:Female; D006801:Humans; D011388:Prolactin / Q000097:blood; D012701:Serotonin / Q000502:physiology*; D014364:Tryptophan / Q000097:blood*
D000597:Amino Acids, Branched-Chain; D012701:Serotonin; D014364:Tryptophan; D011388:Prolactin